Allows you to wear the warning cone (cmss13-devs#6695)

# About the pull request

* makes the cone fit the head slot
* Adds on mob sprites for the cone


# Explain why it's good for the game

I dont need to explain myself.
You all know why i did this.


# Testing Photographs and Procedure
<details>
<summary>Screenshots & Videos</summary>

https://imgur.com/a/8DAFmMK

</details>


# Changelog
:cl: TheManWithNoHands
code: adds flags to cone, allowing it to be worn on head
imageadd: added on mob sprites for cone

/:cl:

code/game/objects/items/tools/cleaning_tools.dm

@@ -99,13 +99,15 @@
 	desc = "This cone is trying to warn you of something!"
 	icon_state = "cone"
 	icon = 'icons/obj/janitor.dmi'
+	item_icons = 'icons/mob/humans/onmob/head_0.dmi'
 	force = 1
 	throwforce = 3
 	throw_speed = SPEED_FAST
 	throw_range = 5
 	w_class = SIZE_SMALL
 	attack_verb = list("warned", "cautioned", "smashed")
-
+	flags_equip_slot = SLOT_HEAD
+	flags_inv_hide = HIDEEARS|HIDETOPHAIR